Test flf trampoline

Signed-off-by: Bob Weinand <bob.weinand@datadoghq.com>

Author: bwoebi

Cargo.lock

@@ -22,6 +22,7 @@ cfg-if = { version = "1.0" }
 cpu-time = { version = "1.0" }
 chrono = { version = "0.4" }
 crossbeam-channel = { version = "0.5", default-features = false, features = ["std"] }
+dynasmrt = "2.0"
 libdd-alloc = {  git = "https://github.com/DataDog/libdatadog", tag = "v25.0.0" }
 libdd-profiling = {  git = "https://github.com/DataDog/libdatadog", tag = "v25.0.0" }
 libdd-common = {  git = "https://github.com/DataDog/libdatadog", tag = "v25.0.0" }

profiling/Cargo.toml

@@ -37,6 +37,7 @@ fn main() {
     let post_startup_cb = cfg_post_startup_cb(vernum);
     let preload = cfg_preload(vernum);
     let fibers = cfg_fibers(vernum);
+    let frameless = cfg_frameless(vernum);
     let run_time_cache = cfg_run_time_cache(vernum);
     let trigger_time_sample = cfg_trigger_time_sample();
     let zend_error_observer = cfg_zend_error_observer(vernum);
@@ -48,6 +49,7 @@ fn main() {
         preload,
         run_time_cache,
         fibers,
+        frameless,
         trigger_time_sample,
         zend_error_observer,
     );
@@ -103,6 +105,7 @@ fn build_zend_php_ffis(
     preload: bool,
     run_time_cache: bool,
     fibers: bool,
+    frameless: bool,
     trigger_time_sample: bool,
     zend_error_observer: bool,
 ) {
@@ -143,6 +146,7 @@ fn build_zend_php_ffis(
     let post_startup_cb = if post_startup_cb { "1" } else { "0" };
     let preload = if preload { "1" } else { "0" };
     let fibers = if fibers { "1" } else { "0" };
+    let frameless = if frameless { "1" } else { "0" };
     let run_time_cache = if run_time_cache { "1" } else { "0" };
     let trigger_time_sample = if trigger_time_sample { "1" } else { "0" };
     let zend_error_observer = if zend_error_observer { "1" } else { "0" };
@@ -159,6 +163,7 @@ fn build_zend_php_ffis(
         .define("CFG_POST_STARTUP_CB", post_startup_cb)
         .define("CFG_PRELOAD", preload)
         .define("CFG_FIBERS", fibers)
+        .define("CFG_FRAMELESS", frameless)
         .define("CFG_RUN_TIME_CACHE", run_time_cache)
         .define("CFG_STACK_WALKING_TESTS", stack_walking_tests)
         .define("CFG_TRIGGER_TIME_SAMPLE", trigger_time_sample)
@@ -394,6 +399,18 @@ fn cfg_fibers(vernum: u64) -> bool {
     }
 }
 
+fn cfg_frameless(vernum: u64) -> bool {
+    if has_check_cfg() {
+        println!("cargo::rustc-check-cfg=cfg(php_frameless)");
+    }
+    if vernum >= 80400 {
+        println!("cargo:rustc-cfg=php_frameless");
+        true
+    } else {
+        false
+    }
+}
+
 fn cfg_php_feature_flags(vernum: u64) {
     if has_check_cfg() {
         println!("cargo::rustc-check-cfg=cfg(php_gc_status, php_zend_compile_string_has_position, php_gc_status_extended, php_frameless, php_opcache_restart_hook, php_zend_mm_set_custom_handlers_ex)");
@@ -409,7 +426,6 @@ fn cfg_php_feature_flags(vernum: u64) {
         println!("cargo:rustc-cfg=php_gc_status_extended");
     }
     if vernum >= 80400 {
-        println!("cargo:rustc-cfg=php_frameless");
         println!("cargo:rustc-cfg=php_opcache_restart_hook");
         println!("cargo:rustc-cfg=php_zend_mm_set_custom_handlers_ex");
     }

profiling/build.rs

@@ -117,6 +117,10 @@ static post_startup_cb_result ddog_php_prof_post_startup_cb(void) {
             return FAILURE;
         }
     }
+    
+#if CFG_FRAMELESS
+    ddog_php_prof_post_startup();
+#endif
 
     _is_post_startup = true;
 

profiling/src/php_ffi.c

@@ -147,6 +147,10 @@ void ddog_php_prof_zend_mm_set_custom_handlers(zend_mm_heap *heap,
 
 zend_execute_data* ddog_php_prof_get_current_execute_data();
 
+#if CFG_FRAMELESS
+void ddog_php_prof_post_startup();
+#endif
+
 #if CFG_FIBERS
 zend_fiber* ddog_php_prof_get_active_fiber();
 zend_fiber* ddog_php_prof_get_active_fiber_test();

profiling/src/php_ffi.h

@@ -137,6 +137,88 @@ pub extern "C" fn ddog_php_prof_interrupt_function(execute_data: *mut zend_execu
     }
 }
 
+#[cfg(php_frameless)]
+mod frameless {
+    #[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
+    use crate::bindings::{zend_flf_functions, zend_flf_handlers};
+
+    #[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
+    mod trampoline {
+        use crate::wall_time::ddog_php_prof_interrupt_function;
+        #[cfg(target_arch = "aarch64")]
+        use dynasmrt::aarch64::Assembler;
+        #[cfg(target_arch = "x86_64")]
+        use dynasmrt::x64::Assembler;
+        use dynasmrt::{dynasm, DynasmApi};
+        use std::ffi::c_void;
+
+        pub unsafe fn generate_wrapper(original: *mut c_void) -> *mut c_void {
+            let mut assembler = Assembler::new().unwrap();
+            let interrupt_addr = ddog_php_prof_interrupt_function as *const () as i64;
+            #[cfg(target_arch = "aarch64")]
+            dynasm!(assembler
+                ; mov x16, original as i64
+                ; blr x16
+                ; mov x0, 0
+                ; mov x16, interrupt_addr
+                ; blr x16
+                ; ret
+            );
+            #[cfg(target_arch = "x86_64")]
+            dynasm!(assembler
+                ; mov rax, QWORD original as i64
+                ; call rax
+                ; mov rdi, 0
+                ; mov rax, QWORD interrupt_addr
+                ; call rax
+                ; ret
+            );
+            let buffer = assembler.finalize().unwrap();
+            let ptr = buffer.as_ptr() as *mut c_void;
+            std::mem::forget(buffer); // TODO: leaks memory
+            ptr
+        }
+    }
+
+    #[no_mangle]
+    pub unsafe extern "C" fn ddog_php_prof_post_startup() {
+        #[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
+        {
+            let mut i = 0;
+            loop {
+                let original = *zend_flf_handlers.add(i);
+                if original.is_null() {
+                    break;
+                }
+                let wrapper = trampoline::generate_wrapper(original);
+                *zend_flf_handlers.add(i) = wrapper;
+                let func = &mut **zend_flf_functions.add(i);
+                let original_info = (*func).internal_function.frameless_function_infos;
+                let mut infos = Vec::new();
+                let mut ptr = original_info;
+                loop {
+                    let info = *ptr;
+                    if info.handler.is_null() {
+                        break;
+                    }
+                    infos.push(info);
+                    ptr = ptr.add(1);
+                }
+                for info in infos.iter_mut() {
+                    if info.handler == original {
+                        info.handler = wrapper;
+                    }
+                }
+                infos.push(crate::bindings::zend_frameless_function_info { handler: std::ptr::null_mut(), num_args: 0 });
+                let new_infos = infos.into_boxed_slice();
+                (*func).internal_function.frameless_function_infos = new_infos.as_ptr() as *mut _;
+                std::mem::forget(new_infos); // TODO: leaks memory
+                i += 1;
+            }
+        }
+    }
+}
+
 /// A wrapper for the `ddog_php_prof_interrupt_function` to call the
 /// previous interrupt handler, if there was one.
 #[no_mangle]